Gah, I'm so frustrated!
I added videos on a timeline on my phone. Once I start editing it on my laptop (macOS Montery 12.5.1) the audio is out of sync on certain clips, but not all. The original files are all fine. When I go back to my phone, the audio on most clips is fine, but sometimes also out of sync, but in a different way from how it was on my laptop. The audio wave also doesn't match up with the actual audio.
The videos are made with my phone, .mp4, 30fps, H.264. With other projects made in the same way I didn't have this problem. I think it started after I installed the new update of Rush, but installing an older version didn't solve the problem. After exporting the file the clips the audio is still out of sync. But when I check the timeline again, certain bits that are out of sync in the export are in sync against in the project?! So confusing.
So to be clear: syncing to the cloud works, but the audio gets out of sync in different ways.